1. Field of the Invention
The present invention relates to an etching processing method and a bevel etching apparatus.
2. Description of the Related Art
A bevel/backside polymer that is adhered to a bevel part (a chamfered part of an edge portion of a wafer) of a semiconductor wafer (which may also be referred to simply as “wafer,” hereinafter) may contaminate a surface of a device, or may adversely affect a yield rate of production of a device.
Thus, a device has been proposed that can apply an etching process so as to remove a bevel/backside polymer by irradiating a laser beam onto a bevel part of a wafer (cf. Patent Document 1 (Japanese Unexamined Patent Publication No. 2010-141237), for example). Output intensity of a laser beam that is irradiated onto a bevel part can be controlled by monitoring and adjusting an electric current that is supplied to a laser generator.
However, even if an electric current that is to be supplied to a laser generator is the same, due to a failure or aged deterioration of a laser generator, output intensity of a laser beam may be varied. Thus, even if an electronic current that is supplied to a laser generator is monitored during operation of a device, it may be difficult to detect an abnormal state for a case in which the electric current that is supplied to the laser generator is not varied and an abnormal value is output as an output value of a laser beam. Consequently, a laser beam with power that is greater than a specified value may be irradiated onto a bevel part of a wafer, and the bevel part may be removed, or a defect may occur in the bevel part.
There is a need for detecting abnormality in an output value of a laser beam during an etching process of a bevel part.